from numpy import *

def loadDataSet():
    fr = open('./bayes.txt')
    datas=[inst.split() for inst in fr.readlines()]
    classVec=[0,1,0,1,0,1]
    return datas, classVec

def createVocabList(dataSet):
    vocabSet = set([])
    for document in dataSet:
        vocabSet = vocabSet | set(document)
    return  list(vocabSet)

def setOfWords2Vec(vocabList, inputSet):
    returnVec = [0] * len(vocabList)
    for word in inputSet:
        if word in vocabList:
            returnVec[vocabList.index(word)] = 1
        else:print("the word :%s is not in my vocabulary!" % word)
    return returnVec

#训练
def trainNB0(trainMatrix, trainCategory):
    numTrainDocs = len(trainMatrix)
    numWords = len(trainMatrix[0])
    pAbusive = sum(trainCategory) / float(numTrainDocs)
    p0Num=zeros(numWords)
    p1Num=zeros(numWords)
    p0Denom=0.0;p1Denom=0.0
    for i in range(numTrainDocs):
        if trainCategory[i] == 1:
            p1Num += trainMatrix[i]
            p1Denom += sum(trainMatrix[i])
        else:
            p0Num += trainMatrix[i]
            p0Denom += sum(trainMatrix[i])
    p1Vect = p1Num/p1Denom
    p0Vect = p0Num/p0Denom
    return p0Vect,p1Vect,pAbusive


def classifyNB(vec2Classify, p0Vec, p1Vec, pClass1):
    p1=sum(vec2Classify*p1Vec)+log(pClass1)
    p0=sum(vec2Classify*p0Vec)+log(1-pClass1)
    if p1 > p0:
        return 1
    else:
        return 0

def testingNB():
    listOPosts,listClasses = loadDataSet()
    myVocabList=createVocabList(listOPosts)
    trainMat=[]
    for postinDoc in listOPosts:
        trainMat.append(setOfWords2Vec(myVocabList, postinDoc))
    p0V,p1V,pAb=trainNB0(array(trainMat), array(listClasses))
    testEntry=['love','my','dalmation']
    thisDoc = array(setOfWords2Vec(myVocabList, testEntry))
    print(testEntry,'classified as:', classifyNB(thisDoc, p0V,p1V,pAb))
    testEntry=['stupid','garbage']
    thisDoc = array(setOfWords2Vec(myVocabList, testEntry))
    print(testEntry, 'classified as:', classifyNB(thisDoc, p0V, p1V, pAb))